JP6169676B2 - Magnetic load sensor and electric brake device - Google Patents

Description

  The present invention relates to a magnetic load sensor and an electric brake device using the magnetic load sensor.

  In general, an electric brake device converts rotation of an electric motor into axial movement of a friction pad, and presses the friction pad against a brake disk to generate a braking force. In order to control this braking force to a desired magnitude, electric brake devices often incorporate a load sensor in a portion that receives a reaction force of a load applied to a friction pad. The load applied to the load sensor (that is, the load applied to the friction pad) is about 30 kN at the maximum, and a load sensor that detects the load with a minute displacement is used to improve the response of the electric brake.

  As a load sensor for detecting such a large load with a minute displacement, for example, one described in Patent Document 1 is known. The load sensor disclosed in Patent Literature 1 is electrically connected between a pair of opposed annular plate-shaped pressing plates, a quartz crystal piezoelectric element sandwiched between the pair of pressing plates, and the quartz piezoelectric element and the pressing plate on one side. It consists of an insulating plate for insulation and a lead wire for taking out the voltage generated by the crystal piezoelectric element.

  In the load sensor of Patent Document 1, when an axial load is input, a compressive stress is generated in the quartz piezoelectric element by the load, and a voltage corresponding to the magnitude of the stress is generated in the quartz piezoelectric element. The magnitude of the load can be detected by measuring the voltage of the crystal piezoelectric element. Further, since the displacement of the pressing plate due to the deformation of the crystal piezoelectric element is minute, when this sensor is incorporated in the electric brake, the responsiveness of the electric brake is not impaired.

  However, since this load sensor directly receives the input load with the crystal piezoelectric element, there is a possibility that the crystal piezoelectric element is cracked or chipped when an impact load or a load oblique to the axial direction is applied. In addition, since the load also acts on the insulating plate that electrically insulates between the piezoelectric element and one pressing plate, high durability is required for the insulating plate, but durability is ensured with inexpensive insulating plates such as resin. It was difficult to do.

  Therefore, the inventor of the present invention has studied a load sensor that can detect a large load with a small displacement and has excellent durability, and developed such a load sensor as shown in FIG. .

  A load sensor 80 shown in FIG. 17 includes a load input member 2, a support member 3, a magnetic target 4, and a magnetic sensor 5. The load input member 2 includes an annular flange portion 6 into which an axial load is input and a cylindrical portion 7 formed integrally and continuously at the radially inner end of the flange portion 6. The flange portion 6 is bent by the axial load applied. The support member 3 supports the outer diameter side portion of the flange portion 6 so that the outer diameter side portion of the flange portion 6 does not move in the axial direction. The magnetic target 4 is fixed to the cylindrical portion 7 of the load input member 2. The magnetic sensor 5 is fixed to the support member 3 so as to detect the magnetic flux generated by the magnetic target 4.

  In the load sensor 80, when an axial load is input to the flange portion 6 of the load input member 2, the magnetic target 4 and the magnetic sensor 5 are relatively displaced by the deflection of the flange portion 6. Since the output signal of the magnetic sensor 5 changes according to the relative displacement, the magnitude of the load can be detected based on the output signal of the magnetic sensor 5. Here, when a load is input to the load sensor 80, the load acts on the flange portion 6 of the load input member 2 to bend the flange portion 6, but does not act on the magnetic sensor 5. For this reason, even when an impact load or a load oblique to the axial direction is applied, it is difficult to fail and high durability can be ensured.

International Publication No. 2011/030839

  By the way, when the sensitivity of the load sensor 80 shown in FIG. 17 is to be increased, it is conceivable to increase the deflection of the flange portion 6 with respect to the load by thinning the flange portion 6 of the load input member 2. When 6 is made thin, the problem that durability falls will arise. On the other hand, if the flange portion 6 is made thicker in order to increase the durability of the load sensor 80, the flange portion 6 becomes difficult to bend, which causes a problem that the sensitivity of the load sensor 80 is lowered. That is, the sensitivity and durability of the load sensor 80 are in a trade-off relationship in which if one is pursued, the other must be sacrificed.

  In addition, as a method of increasing the sensitivity of the load sensor 80 without making the flange portion 6 of the load input member 2 thin, for example, the load is deformed when a load is input between the contact surfaces of the flange portion 6 and the support member 3. It is conceivable that another member such as a spring is incorporated and the relative displacement between the magnetic target 4 and the magnetic sensor 5 is increased by deformation of the other member. However, in this case, a hysteresis error due to friction occurs, and the load sensor 80 is detected. Accuracy cannot be ensured. That is, when another member such as a spring is incorporated, energy loss caused by friction with the other member causes an increase in load (that is, when the deflection of the flange portion 6 increases) and a decrease in load (that is, the deflection of the flange portion 6). There arises a problem that a difference in load detection value occurs when the value decreases.

  The problem to be solved by the present invention is to provide a load sensor having both high durability and high sensitivity.

  The inventor of the present invention has analyzed the stress generated in the load input member 2 when an axial load is input to the load sensor 80 shown in FIG. 17, and as shown in FIG. It was found that a high tensile stress is generated in the inner diameter side portion of the flange portion 6 (particularly, the portion continuing to the cylindrical portion 7 of the flange portion 6), but only a low stress is generated in the outer diameter side portion of the flange portion 6. The inner diameter side portion of the flange portion 6 where high tensile stress is generated ensures rigidity to ensure high durability, and the outer diameter side portion of the flange portion 6 where only low stress is generated is high in the load sensor 80. In order to provide sensitivity, the inventors have focused on the point that both high durability and high sensitivity of the load sensor 80 can be achieved if the rigidity is lowered to make it easy to bend.

  Based on this viewpoint, in the present invention, the magnetic target that generates magnetic flux, the magnetic sensor that detects the magnetic flux generated by the magnetic target, the annular flange portion, and the radially inner end of the flange portion are integrally integrated. And a support member that supports the outer diameter side portion of the flange portion so as not to move in the axial direction. The magnetic target and the magnetic sensor include the flange One of the magnetic target and the magnetic sensor is fixed to the cylindrical portion of the load input member so that the relative displacement between the magnetic target and the magnetic sensor is caused by the deflection of the flange portion when an axial load is input to the portion. The flange as a magnetic load sensor that is fixed to the support member and detects the magnitude of the axial load based on the magnetic flux detected by the magnetic sensor Of the outer diameter side portion, to provide a magnetic load sensor low rigidity portion is formed to have an axial thickness smaller axial thickness than the radial inner end of the flange portion.

  In this way, since the axial thickness of the inner diameter side portion of the flange portion can be secured, a relatively high tensile stress is applied to the inner diameter side portion of the flange portion when an axial load is input to the load input member. Even if this occurs, damage to the load input member due to the tensile stress is prevented, and the durability of the load sensor can be ensured. In addition, when an axial load is input to the load input member, the flange portion is bent relatively large due to the deformation of the low-rigidity portion, so that the axial thickness of the flange portion is the same over the entire surface, The load can be detected with high sensitivity.

  As the low-rigidity portion, for example, a tapered portion where the axial thickness of the flange portion gradually decreases from the inner diameter side to the outer diameter side of the flange portion can be employed. In this way, since the change in the thickness of the low-rigidity portion along the radial direction of the flange portion is smooth, it is possible to prevent stress concentration from occurring in the low-rigidity portion and ensure the durability of the flange portion. It is possible.

  In this case, the low-rigidity portion can be formed such that the axial thickness of the flange portion decreases linearly from the inner diameter side toward the outer diameter side. If it does in this way, processing of a low-rigidity part is easy and it is low-cost. The low-rigidity portion may be formed such that the axial thickness of the flange portion decreases like an arcuate concave curve from the inner diameter side toward the outer diameter side.

  In addition, as the low rigidity portion, for example, a portion formed in a step shape in which the axial thickness of the flange portion gradually decreases from the inner diameter side to the outer diameter side of the flange portion, A plurality of axial notches formed in the outer circumference at equal intervals in the circumferential direction, a plurality of radial grooves formed at equal intervals in the circumferential direction on the side surface of the flange portion, and the flange portion A circumferential groove or the like formed on the side surface so as to be concentric with the flange portion can be employed.

  As the magnetic target, a plurality of permanent magnets having a magnetization direction in a direction orthogonal to the relative displacement direction of the magnetic target and the magnetic sensor, and magnetic poles having opposite polarities in the relative displacement direction of the magnetic target and the magnetic sensor It is preferable to use one arranged in a line and arrange the magnetic sensor in the vicinity of the boundary between the adjacent magnetic poles.

  In this way, the output signal of the magnetic sensor changes sharply with respect to the relative displacement in the axial direction of the magnetic target and the magnetic sensor, while it does not change much with respect to the relative displacement in directions other than the axial direction. Indicates directionality. Therefore, the output signal of the magnetic sensor is hardly affected by external vibration, and the magnitude of the load can be detected with stable accuracy.

  Moreover, in this invention, the electric brake device provided with the said magnetic type load sensor is provided.

  In the magnetic load sensor of the present invention, a low-rigidity portion having an axial thickness smaller than the axial thickness of the radially inner end of the flange portion is formed on the outer diameter side portion of the flange portion. Low rigidity part of the flange part that generates a low stress when an axial load is input while at the same time ensuring the axial thickness of the inner diameter side part of the flange part where a high tensile stress occurs when an axial load is input By deforming, the flange portion can be bent relatively large. Therefore, it is possible to achieve both high durability and high sensitivity.

Sectional drawing which shows the magnetic type load sensor of 1st Embodiment of this invention FIG. 1 is an enlarged cross-sectional view of the magnetic load sensor shown in FIG. Right side view of the magnetic load sensor shown in FIG. FIG. 2 is an enlarged sectional view showing an example in which the arrangement of the magnetic target and the magnetic sensor shown in FIG. 2 is changed. Sectional drawing which shows the electric brake device using the magnetic type load sensor shown in FIG. Fig. 5 is an enlarged cross-sectional view of the vicinity of the linear actuator. Sectional drawing along the VII-VII line of FIG. Sectional drawing which shows the electric brake device which uses the ball screw mechanism instead of the planetary roller mechanism shown in FIG. Sectional drawing which shows the electric brake device which uses the ball ramp mechanism instead of the planetary roller mechanism shown in FIG. Sectional view along line XX in FIG. 10A is a diagram showing the relationship between the ball and the inclined groove shown in FIG. 10, and FIG. 10B is a diagram showing a state in which the rotation disk and the linear motion disk are relatively rotated from the state shown in FIG. Figure (A) The left view which shows the magnetic type load sensor of 2nd Embodiment of this invention, (b) is sectional drawing of the magnetic type load sensor shown to (a). (A) is a left view which shows the magnetic type load sensor of 3rd Embodiment of this invention, (b) is sectional drawing of the magnetic type load sensor shown to (a). (A) The left view which shows the magnetic type load sensor of 4th Embodiment of this invention, (b) is sectional drawing of the magnetic type load sensor shown to (a). (A) is a left view which shows the magnetic type load sensor of 5th Embodiment of this invention, (b) is sectional drawing of the magnetic type load sensor shown to (a). (A) is a left view which shows the magnetic type load sensor of 6th Embodiment of this invention, (b) is sectional drawing of the magnetic type load sensor shown to (a). Sectional drawing which shows the magnetic type load sensor of a comparative example (A) is a figure which shows the result of having analyzed the stress which arises in a flange part when an axial direction load is input into the magnetic type load sensor of the comparative example shown in FIG. 17, (b) is a magnetic type load sensor shown in FIG. The figure which shows the result of analyzing the stress generated in the flange part when the axial load is input (A) is a figure which shows the result of having analyzed the displacement which arises in each point inside a flange part, when an axial load is input into the magnetic type load sensor of the comparative example shown in FIG. 17, (b) shows in FIG. The figure which shows the result of analyzing the displacement which arises in each point inside a flange part when an axial load is inputted into a magnetic type load sensor

  1 to 3 show a magnetic load sensor 1 according to a first embodiment of the present invention. The magnetic load sensor 1 includes a load input member 2 to which an axial load is input, a support member 3 that supports the load input member 2, a magnetic target 4 that generates magnetic flux, and a magnetic flux that is generated by the magnetic target 4. It consists of a magnetic sensor 5 to detect.

  The load input member 2 includes an annular plate-like flange portion 6 that faces the support member 3 and a cylindrical portion 7 that is integrally and continuously formed at the radially inner end of the flange portion 6. The flange portion 6 and the cylindrical portion 7 are formed of a metal such as iron.

  The cylindrical portion 7 is formed so as to protrude in the axial direction from the radially inner end of the flange portion 6 toward the support member 3, and a portion protruding toward the support member 3 side extends in the radial direction with the inner periphery of the support member 3. Opposite. A magnetic target 4 is fixed to a portion of the cylindrical portion 7 protruding to the support member 3 side. A magnetic sensor 5 is fixed to the inner periphery of the support member 3 so as to face the magnetic target 4 in the radial direction. The cylindrical portion 7 is formed so as to protrude from the radially inner end of the flange portion 6 to the side opposite to the support member 3. A plurality of bearings 8 are mounted on the inner periphery of the cylindrical portion 7 at intervals in the axial direction.

  A low rigidity portion 6 a is formed on the outer diameter side portion of the flange portion 6. The low-rigidity portion 6a is a portion in which the rigidity is lowered by giving the axial thickness smaller than the axial thickness T of the radially inner end of the flange portion 6. In this embodiment, the low-rigidity portion 6a is a portion formed in a tapered shape in which the axial thickness of the flange portion 6 gradually decreases from the inner diameter side of the flange portion 6 toward the outer diameter side. And, when the axial load is inputted to the load input member 2, the low rigidity portion 6a is deformed, so that the axial thickness of the flange portion 6 is made uniform over the entire surface as shown in FIG. The flange portion 6 is greatly bent. On the other hand, the inner diameter side portion of the flange portion 6 is formed so that the axial thickness is constant from the inner diameter side toward the outer diameter side.

  The support member 3 is made of the same metal as the load input member 2. The support member 3 is formed on the outer diameter side portion of the surface of the annular plate portion 9 facing the flange portion 6 of the load input member 2 at an interval in the axial direction and the flange portion 6 of the annular plate portion 9. The annular support protrusion 10 is formed, and a fitting cylinder portion 11 formed on the outer diameter side of the support protrusion 10.

  The support protrusion 10 supports the outer diameter side end portion of the flange portion 6 so as not to move in the axial direction, and maintains the axial interval between the annular plate portion 9 and the flange portion 6. The fitting cylinder part 11 is fitted to the outer periphery of the flange part 6, and the fitting holds the relative position of the support member 3 and the cylindrical part 7 in the radial direction.

  Here, if the fitting of the fitting cylinder part 11 and the flange part 6 is a fitting with a tightening margin, the flange part 6 can be prevented from coming off from the fitting cylinder part 11 by the fitting. When the fitting between the fitting cylinder part 11 and the flange part 6 is a loose fit, the flange part 6 is fitted by crimping the fitting part between the flange part 6 and the fitting cylinder part 11 to cause plastic deformation. It is possible to prevent the cylinder portion 11 from coming off.

  The magnetic target 4 has two magnetizing directions in a direction perpendicular to the relative displacement direction of the magnetic target 4 and the magnetic sensor 5 due to the deflection of the flange portion 6 of the load input member 2 (here, the radial direction of the cylindrical portion 7). Of the permanent magnet 12. The two permanent magnets 12 are adjacent to each other such that magnetic poles having opposite polarities to the respective permanent magnets 12 (that is, the N pole of one permanent magnet 12 and the S pole of the other permanent magnet 12) are aligned in the axial direction. Are arranged.

  For example, when a neodymium magnet is used as the permanent magnet 12, a powerful magnetic flux can be generated in a space-saving manner. May be. When a samarium cobalt magnet, a samarium iron nitride magnet, or an alnico magnet is used, it is possible to suppress a decrease in magnetic flux accompanying a temperature increase of the permanent magnet 12. Further, when a praseodymium magnet is used, the mechanical strength of the permanent magnet 12 can be improved.

  As shown in FIG. 3, the magnetic sensor 5 is disposed so as to face the magnetic target 4 in the direction perpendicular to the axis (radial direction in the drawing) in the vicinity of the boundary between adjacent magnetic poles of the two permanent magnets 12. As the magnetic sensor 5, it is possible to use a magnetoresistive element (so-called MR sensor) or a magneto-impedance element (so-called MI sensor). However, using a Hall IC is advantageous in terms of cost and has a heat resistance. Since a high Hall IC is commercially available, it is suitable for electric brake applications.

  As shown by the arrow in FIG. 1, the magnetic load sensor 1 is configured such that when an axial load in a direction from the flange portion 6 toward the support member 3 is input to the load input member 2, the load input member is generated by the axial load. 2 is bent in the axial direction with the end on the outer diameter side as a fulcrum, and with this deflection, the magnetic target 4 and the magnetic sensor 5 are relatively displaced in the axial direction, and the relative displacement between the magnetic target 4 and the magnetic sensor 5 is caused. Accordingly, the output signal of the magnetic sensor 5 changes. Therefore, the axial direction applied to the flange portion 6 based on the output signal of the magnetic sensor 5 by grasping in advance the relationship between the magnitude of the axial load input to the flange portion 6 and the output signal of the magnetic sensor 5. The magnitude of the load can be detected.

  Here, the relative change amount of the magnetic target 4 and the magnetic sensor 5 when an axial load is input to the magnetic load sensor 1 is extremely small. For example, when this magnetic load sensor 1 is incorporated in an electric brake device to be described later, a maximum axial load of 30 kN is input to the magnetic load sensor 1, and the magnetic target 4 and the magnetic sensor 5 at this time The amount of relative change in the axial direction is about 0.1 mm to 0.2 mm. Here, the magnetic load sensor 1 is arranged at the boundary between the north pole and the south pole because the north pole and south pole of the two permanent magnets 12 whose radial direction is the magnetization direction are adjacent to each other in the axial direction. In the vicinity of the magnetic sensor 5, the magnetic flux intersecting in the axial direction exists at a high density. Therefore, the output signal of the magnetic sensor 5 changes sharply with respect to a slight relative displacement in the axial direction between the magnetic target 4 and the magnetic sensor 5. Therefore, although the relative displacement between the magnetic target 4 and the magnetic sensor 5 is extremely small, the magnitude of the axial load acting on the flange portion 6 can be detected.

  FIG. 17 shows a magnetic load sensor of a comparative example for the above embodiment. This magnetic load sensor is formed such that the flange portion 6 does not have the low rigidity portion 6a, and the axial thickness of the flange portion 6 is the same over the entire surface. Other configurations are the same as those in the above embodiment.

  The result of analyzing the stress generated in the flange portion 6 when an axial load is input to the magnetic load sensor of the comparative example shown in FIG. 17 and the axial load is input to the magnetic load sensor 1 of the above embodiment. 18 (a) and 18 (b) show the results of analyzing the stress generated in the flange portion 6 at the time. Also, at this time, the result of analyzing the displacement generated at each point inside the flange portion 6 of the comparative example shown in FIG. 17 and the result of analyzing the displacement generated at each point inside the flange portion 6 of the above embodiment, It shows to Fig.19 (a), (b). These analyzes were performed on a 1/36 cut model.

  According to this analysis result, as shown in FIGS. 18A and 18B, high tensile stress is generated in the inner diameter side portion of the flange portion 6 (particularly, the portion continuous to the cylindrical portion 7 of the flange portion 6). Only a low stress is generated in the outer diameter side portion of the flange portion 6. In general, the durability of a member that receives a load is determined by the maximum tensile stress generated at that time and the rigidity of the portion. Therefore, the axial thickness T of the inner diameter side portion of the flange portion 6 affects the durability of the load input member 2, but the axial thickness of the outer diameter side portion of the flange portion 6 affects the durability of the load input member 2. It turns out that there is almost no influence. That is, when the case where the low-rigidity portion 6a is not provided in the flange portion 6 as shown in FIG. 17 and the case where the low-rigidity portion 6a is provided in the flange portion 6 as in the embodiment described above, If the axial thickness T at the radially inner end is the same, its durability is hardly changed.

  On the other hand, the displacement amount of each part of the flange portion 6 shows the displacement distribution as shown in FIG. 19A when the low rigidity portion 6a is not provided in the flange portion 6 as shown in FIG. When the low rigidity part 6a is provided in the flange part 6 like embodiment, as shown in FIG.19 (b), compared with FIG.19 (a), it is 1.5 in the radial direction inner end. As a result, the displacement amount is about double. That is, as shown in FIG. 17, the flange portion 6 is greatly improved when the flange portion 6 is provided with the low rigidity portion 6a as compared with the case where the flange portion 6 is not provided with the low rigidity portion 6a. You can see that it bends greatly.

  As described above, the magnetic load sensor 1 of the above embodiment has a low axial thickness at the outer diameter side portion of the flange portion 6 that is smaller than the axial thickness T of the radially inner end of the flange portion 6. Since the rigid portion 6a is formed, the axial thickness of the inner diameter side portion of the flange portion 6 that generates a high tensile stress when an axial load is input is secured, and at the same time when the axial load is input. By deforming the low-rigidity portion 6a of the flange portion 6 that generates only low stress, the flange portion 6 can be bent relatively large. Therefore, it is possible to achieve both high durability and high sensitivity.

  Further, when a load is input, the magnetic load sensor 1 acts on the flange portion 6 to bend the flange portion 6 but does not act on the magnetic sensor 5. Therefore, even if an impact load or a load oblique to the axial direction is applied, the magnetic sensor 5 is unlikely to fail and high durability can be ensured.

  Further, in this magnetic load sensor 1, the load input member 2 and the support member 3 are formed of materials having the same linear expansion coefficient, so that when the temperature rises, the load input member 2 and the support member 3 Thermal expansion at the same rate. For this reason, relative displacement between the magnetic target 4 and the magnetic sensor 5 due to temperature change is unlikely to occur, and errors due to temperature change are unlikely to occur.

  1 to 3, the magnetic target 4 is fixed to the cylindrical portion 7 of the load input member 2 and the magnetic sensor 5 is fixed to the support member 3. However, the relationship between the magnetic target 4 and the magnetic sensor 5 is reversed. May be. That is, as shown in FIG. 4, the magnetic sensor 5 may be fixed to the cylindrical portion 7 of the load input member 2 and the magnetic target 4 may be fixed to the support member 3.

  1 to 4, in order to make the output signal of the magnetic sensor 5 change sharply with respect to a slight deflection of the flange portion 6 in the axial direction, the load input member 2 and the support member 3 are arranged in the radial direction. A configuration is adopted in which a facing surface is provided and the magnetic target 4 and the magnetic sensor 5 are fixed to the facing surface. However, the load input member 2 and the support member 3 are provided with an axial facing surface, and the magnetic target is provided on the facing surface. 4 and the magnetic sensor 5 may be fixed.

  5 to 7 show an electric brake device for a vehicle using the magnetic load sensor 1 described above.

  The electric brake device includes a caliper body 17 having a shape in which opposed pieces 14 and 15 that are opposed to each other with a bridge 16 that is opposed to a brake disc 13 that rotates integrally with a wheel, and a facing surface of the opposed piece 15 that faces the brake disc 13. And a pair of left and right friction pads 20 and 21.

  The friction pad 21 is provided between the opposing piece 15 and the brake disc 13 and is supported by a pad pin (not shown) attached to the caliper body 17 so as to be movable in the axial direction of the brake disc 13. The other friction pad 20 is attached to the opposing piece 14 on the opposite side. The caliper body 17 is supported so as to be slidable in the axial direction of the brake disc 13.

  As shown in FIG. 6, the linear actuator 19 includes a rotating shaft 22, a plurality of planetary rollers 23 that are in rolling contact with the outer peripheral cylindrical surface of the rotating shaft 22, and an outer ring that is disposed so as to surround these planetary rollers 23. It has the member 24, the carrier 25 which hold | maintains the planetary roller 23 so that rotation and revolution are possible, and the magnetic type load sensor 1 arrange | positioned in the axial direction back of the outer ring member 24.

  The rotation shaft 22 is rotationally driven by the rotation of the electric motor 26 shown in FIG. The rotating shaft 22 is inserted into the receiving hole 18 with one end protruding from the opening on the rear side in the axial direction of the receiving hole 18 formed so as to penetrate the opposing piece 15 in the axial direction, and into the protruding portion from the receiving hole 18. The gear 27 is spline fitted to prevent rotation. The gear 27 is covered with a lid 29 fixed with bolts 28 so as to close the opening on the rear side in the axial direction of the accommodation hole 18. The lid 29 incorporates a bearing 30 that rotatably supports the rotary shaft 22.

  As shown in FIG. 7, the planetary roller 23 is in rolling contact with the outer peripheral cylindrical surface of the rotating shaft 22, and the planetary roller 23 is caused by friction between the planetary roller 23 and the rotating shaft 22 when the rotating shaft 22 rotates. Also comes to rotate. A plurality of planetary rollers 23 are provided at regular intervals in the circumferential direction.

  As shown in FIG. 6, the outer ring member 24 is accommodated in an accommodation hole 18 provided in the facing piece 15 of the caliper body 17, and is supported so as to be slidable in the axial direction on the inner periphery of the accommodation hole 18. At the front end in the axial direction of the outer ring member 24, an engagement recess 32 that engages with an engagement protrusion 31 formed on the back surface of the friction pad 21 is formed, and the engagement protrusion 31 and the engagement recess 32 are engaged. Thus, the outer ring member 24 is prevented from rotating with respect to the caliper body 17.

  A spiral ridge 33 is provided on the inner periphery of the outer ring member 24, and a circumferential groove 34 that engages with the spiral ridge 33 is provided on the outer periphery of the planetary roller 23, so that the planetary roller 23 rotates. The spiral ridge 33 of the outer ring member 24 is guided by the circumferential groove 34 so that the outer ring member 24 moves in the axial direction. Here, the circumferential groove 34 having a lead angle of 0 degree is provided on the outer periphery of the planetary roller 23, but a spiral groove having a lead angle different from that of the spiral protrusion 33 may be provided instead of the circumferential groove 34.

  The carrier 25 includes a carrier pin 25A that rotatably supports the planetary roller 23, an annular carrier plate 25B that maintains a constant circumferential interval at the front end in the axial direction of each carrier pin 25A, and an axial direction of each carrier pin 25A. And an annular carrier body 25C that maintains a constant circumferential interval at the rear end. The carrier plate 25B and the carrier body 25C face the planetary roller 23 in the axial direction, and are connected via a connecting rod 35 disposed between the planetary rollers 23 adjacent in the circumferential direction.

  The carrier main body 25 </ b> C is supported on the rotary shaft 22 via the sliding bearing 36 and is rotatable relative to the rotary shaft 22. A thrust bearing 37 is installed between the planetary roller 23 and the carrier body 25C to block transmission of the rotation of the planetary roller 23 to the carrier body 25C.

  Each carrier pin 25A is urged radially inward by a reduced-diameter ring spring 38 mounted so as to circumscribe a plurality of carrier pins 25A arranged at intervals in the circumferential direction. Due to the biasing force of the reduced diameter ring spring 38, the outer periphery of the planetary roller 23 is pressed against the outer periphery of the rotating shaft 22, and slippage between the rotating shaft 22 and the planetary roller 23 is prevented. In order to apply the urging force of the reduced diameter ring spring 38 over the entire axial length of the planetary roller 23, reduced diameter ring springs 38 are provided at both ends of the carrier pin 25A.

  The magnetic load sensor 1 is fitted in the accommodation hole 18 in the direction in which the support member 3 faces the axial direction rearward of the flange portion 6 of the load input member 2. A spacer 39 that revolves integrally with the carrier 25 and a thrust bearing 40 that transmits an axial load between the spacer 39 and the magnetic load sensor 1 are incorporated between the carrier 25 and the magnetic load sensor 1. ing. The thrust bearing 40 is provided so as to contact the inner diameter side portion of the flange portion 6 of the load input member 2, and an axial load is applied from the spacer 39 to the inner diameter side portion of the flange portion 6 via the thrust bearing 40. It is designed to be entered. A rotating shaft 22 is rotatably supported by a bearing 8 incorporated in the cylindrical portion 7 of the load input member 2.

  The magnetic load sensor 1 is restricted from moving rearward in the axial direction by locking the outer peripheral edge of the support member 3 with a retaining ring 41 attached to the inner periphery of the accommodation hole 18. The magnetic load sensor 1 supports the carrier body 25 </ b> C in the axial direction via the spacer 39 and the thrust bearing 40, thereby restricting the movement of the carrier 25 in the rearward direction in the axial direction. The carrier 25 is also restricted from moving forward in the axial direction by a retaining ring 42 attached to the front end of the rotating shaft 22 in the axial direction. Therefore, the movement of the carrier 25 in both the axial front and the axial rear is restricted, and the planetary roller 23 held by the carrier 25 is also restricted in the axial movement.

  Next, an operation example of the above-described electric brake device will be described.

  When the electric motor 26 is operated, the rotating shaft 22 rotates, and the planetary roller 23 revolves around the rotating shaft 22 while rotating around the carrier pin 25A. At this time, the outer ring member 24 and the planetary roller 23 move relative to each other in the axial direction due to the engagement between the spiral ridge 33 and the circumferential groove 34, but the planetary roller 23 is restricted from moving in the axial direction together with the carrier 25. The roller 23 does not move in the axial direction, and the outer ring member 24 moves in the axial direction. In this manner, the linear actuator 19 converts the rotation of the rotating shaft 22 driven by the electric motor 26 into the axial movement of the outer ring member 24 and applies an axial load to the friction pad 21 by the outer ring member 24. As a result, the friction pad 21 is pressed against the brake disc 13 to generate a braking force.

  Here, when the outer ring member 24 applies an axial load to the friction pad 21, an axial rearward reaction force acts on the outer ring member 24, and the reaction force is generated by the planetary roller 23, the carrier 25, and the spacer 39. The magnetic load sensor 1 receives the thrust bearing 40. And the flange part 6 of the magnetic type load sensor 1 bends in the axial direction rearward by the reaction force, and the magnetic target 4 and the magnetic sensor 5 are relatively displaced. At this time, since the output signal of the magnetic sensor 5 changes according to the relative displacement between the magnetic target 4 and the magnetic sensor 5, the magnitude of the axial load can be detected based on the output signal of the magnetic sensor 5. Moreover, highly accurate load control is realizable by feedback-controlling the braking force of an electric brake device using the output signal of this magnetic sensor 5. FIG.

  In this electric brake device, as a linear motion mechanism that converts the rotation of the rotary shaft 22 into the axial movement of the outer ring member 24, a plurality of planetary rollers 23 that are in rolling contact with the outer peripheral cylindrical surface of the rotary shaft 22 and the planetary rollers 23 are provided. A carrier 25 that is capable of rotating and revolving and that is restricted from moving in the axial direction, an outer ring member 24 that is disposed so as to surround a plurality of planetary rollers 23, and a spiral ridge provided on the inner periphery of the outer ring member 24 33 and a planetary roller mechanism comprising a spiral groove or a circumferential groove 34 provided on the outer periphery of each planetary roller 23 so as to engage with the spiral ridge 33, but a linear motion mechanism of another configuration The magnetic load sensor 1 can also be incorporated into an electric brake device employing the above.

  For example, FIG. 8 shows an example of an electric brake device that employs a ball screw mechanism as a linear motion mechanism. Hereinafter, portions corresponding to the above embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 8, the linear actuator 19 is formed on the outer periphery of the rotating shaft 22, a screw shaft 50 provided integrally with the rotating shaft 22, a nut 51 provided so as to surround the screw shaft 50, and the screw shaft 50. A plurality of balls 54 incorporated between the formed screw groove 52 and the screw groove 53 formed on the inner periphery of the nut 51, and a return tube (not shown) for returning the ball 54 from the end point of the screw groove 53 of the nut 51 to the starting point. The magnetic load sensor 1 is disposed behind the nut 51 in the axial direction.

  The nut 51 is accommodated in the accommodation hole 18 provided in the facing piece 15 so as to be slidable in the axial direction while being prevented from rotating with respect to the caliper body 17. A spacer 39 that rotates integrally with the screw shaft 50 is provided at the rear end in the axial direction of the screw shaft 50, and the spacer 39 is supported by the magnetic load sensor 1 via a thrust bearing 40. Here, the magnetic load sensor 1 supports the nut 51 in the axial direction via the spacer 39, the thrust bearing 40, and the screw shaft 50, thereby restricting the movement of the nut 51 in the axial rearward direction. .

  The electric brake device rotates the rotary shaft 22 to rotate the screw shaft 50 and the nut 51 relative to each other, move the nut 51 forward in the axial direction, and apply an axial load to the friction pad 21. At this time, a reaction force acting rearward in the axial direction acts on the screw shaft 50, and the reaction force is received by the magnetic load sensor 1 via the spacer 39 and the thrust bearing 40. And the flange part 6 of the magnetic type load sensor 1 bends in the axial direction rearward by the reaction force, and the magnetic target 4 and the magnetic sensor 5 are relatively displaced. Therefore, as in the above embodiment, the output signal of the magnetic sensor 5 changes according to the magnitude of the axial load applied to the friction pad 21, and the magnitude of the axial load is based on the output signal of the magnetic sensor 5. (Pressing force of the friction pad 21) can be detected.

  FIG. 9 shows an example of an electric brake device that employs a ball ramp mechanism as a linear motion mechanism.

  In FIG. 9, the electric brake device includes a rotating shaft 22, a rotating disk 60 that is prevented from rotating on the outer periphery of the rotating shaft 22, a linearly-moving disk 61 that is disposed in front of the rotating disk 60 in the axial direction, A plurality of balls 62 sandwiched between the disk 60 and the linear motion disk 61, and the magnetic load sensor 1 disposed behind the linear motion disk 61 in the axial direction.

  The linear motion disk 61 is accommodated in an accommodation hole 18 provided in the opposing piece 15 so as to be slidable in the axial direction while being prevented from rotating with respect to the caliper body 17. A spacer 39 that rotates integrally with the rotary disk 60 is provided at the rear end in the axial direction of the rotary disk 60, and the spacer 39 is supported by the magnetic load sensor 1 via a thrust bearing 40. Here, the magnetic load sensor 1 regulates the movement of the rotary disk 60 in the axial direction rearward by supporting the rotary disk 60 in the axial direction via the spacer 39 and the thrust bearing 40.

  As shown in FIGS. 9 and 10, an inclined groove 63 whose depth gradually decreases along one circumferential direction is formed on the surface of the rotating disk 60 that faces the linear moving disk 61. An inclined groove 64 whose depth gradually decreases along the other direction of the circumferential direction is formed on the surface facing the rotating disk 60. As shown in FIG. 11 (a), the ball 62 is incorporated between the inclined groove 63 of the rotating disk 60 and the inclined groove 64 of the linear motion disk 61. As shown in FIG. When the rotating disk 60 rotates relative to the disk 61, the balls 62 roll in the inclined grooves 63 and 64, and the interval between the rotating disk 60 and the linearly moving disk 61 is increased.

  This electric brake device rotates the rotary shaft 22 to rotate the linear motion disc 61 and the rotary disc 60 relative to each other, thereby moving the linear motion disc 61 forward in the axial direction and applying an axial load to the friction pad 21. To do. At this time, a reaction force acting rearward in the axial direction acts on the rotating disk 60, and the reaction force is received by the magnetic load sensor 1 via the spacer 39 and the thrust bearing 40. And the flange part 6 of the magnetic type load sensor 1 bends in the axial direction rearward by the reaction force, and the relative position of the magnetic target 4 and the magnetic sensor 5 changes. Therefore, as in the above embodiment, the output signal of the magnetic sensor 5 changes according to the magnitude of the axial load applied to the friction pad 21, and the magnitude of the axial load is based on the output signal of the magnetic sensor 5. It is possible to detect the pressure (the pressing force of the friction pad 21).

  12A and 12B show a magnetic load sensor 70 according to a second embodiment of the present invention. Portions corresponding to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  A low-rigidity portion 6a formed in a step shape in which the axial thickness of the flange portion 6 gradually decreases from the inner diameter side to the outer diameter side of the flange portion 6 is formed on the outer diameter side portion of the flange portion 6. Has been. And, when the axial load is inputted to the load input member 2, the low rigidity portion 6a is deformed, so that the axial thickness of the flange portion 6 is made uniform over the entire surface as shown in FIG. The flange portion 6 is greatly bent.

  13 (a) and 13 (b) show a magnetic load sensor 71 according to a third embodiment of the present invention. Portions corresponding to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  13 (a) and 13 (b), the low-rigidity portion 6a of the outer diameter side portion of the flange portion 6 has a plurality of cuts penetrating in the axial direction formed at equal intervals in the circumferential direction on the outer periphery of the flange portion 6. It is a lack. When the axial load is input to the load input member 2, the low rigidity portion 6a (that is, the notch portion) is deformed, so that the axial thickness of the flange portion 6 is increased over the entire surface as shown in FIG. The flange portion 6 bends more greatly than the case where they are the same.

  14 (a) and 14 (b) show a magnetic load sensor 72 according to a fourth embodiment of the present invention. Portions corresponding to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  14A and 14B, the low rigidity portion 6 a of the outer diameter side portion of the flange portion 6 is a plurality of radial grooves formed at equal intervals in the circumferential direction on the side surface of the flange portion 6. When the axial load is input to the load input member 2, the low rigidity portion 6a (that is, the radial groove portion) is deformed, so that the axial thickness of the flange portion 6 is reduced over the entire surface as shown in FIG. Therefore, the flange portion 6 bends more than the case where it is the same.

  15 (a) and 15 (b) show a magnetic load sensor 73 according to a fifth embodiment of the present invention. Portions corresponding to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIGS. 15A and 15B, the low-rigidity portion 6 a on the outer diameter side portion of the flange portion 6 is a circumferential groove formed on the side surface of the flange portion 6 so as to be concentric with the flange portion 6. When the axial load is input to the load input member 2, the low rigidity portion 6a (that is, the circumferential groove portion) is deformed, so that the axial thickness of the flange portion 6 is reduced over the entire surface as shown in FIG. Therefore, the flange portion 6 bends more than the case where it is the same.

  FIGS. 16A and 16B show a magnetic load sensor 74 according to a sixth embodiment of the present invention. Portions corresponding to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIGS. 16A and 16B, the axial thickness of the flange portion 6 decreases in an arcuate concave curve from the inner diameter side toward the outer diameter side at the outer diameter side portion of the flange portion 6. A low-rigidity portion 6a is formed on the surface. And, when the axial load is inputted to the load input member 2, the low rigidity portion 6a is deformed, so that the axial thickness of the flange portion 6 is made uniform over the entire surface as shown in FIG. The flange portion 6 is greatly bent.

  In the electric brake device described in the first embodiment, the magnetic load sensors 70 to 74 of the second to sixth embodiments can be used instead of the magnetic load sensor 1 of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Magnetic load sensor 2 Load input member 3 Support member 4 Magnetic target 5 Magnetic sensor 6 Flange part 6a Low-rigidity part 7 Cylindrical part 12 Permanent magnet 70 Magnetic load sensor 71 Magnetic load sensor 72 Magnetic load sensor 73 Magnetic load Sensor 74 Magnetic load sensor T Axial thickness

Claims (3)

A magnetic target (4) for generating magnetic flux;
A magnetic sensor (5) for detecting a magnetic flux generated by the magnetic target (4);
A load input member (2) comprising an annular flange portion (6) and a hollow cylindrical portion (7) formed integrally and continuously on the flange portion (6);
An annular support member (3) and for supporting so as not to move the annular flange portion (6) in the axial direction,
When the axial load is input to the annular flange portion (6), the magnetic target (4) and the magnetic sensor (5) are deformed by the deflection of the flange portion (6). One of the magnetic target (4) and the magnetic sensor (5 ) is fixed to the cylindrical portion (7) of the load input member (2) , and the other is the annular support member (3) so that 5) is relatively displaced. A magnetic load sensor that detects the magnitude of the axial load based on the magnetic flux detected by the magnetic sensor (5),
A magnetic load sensor in which a low rigidity portion (6a) having an axial thickness (T) smaller than an axial thickness (T) of another range is formed in a partial range of the flange portion (6).   The low-rigidity portion (6a) is lower than the deflection of the flange portion (6) when the axial load is input to the flange portion (6) when the low-rigidity portion (6a) is not provided. The magnetism according to claim 1, wherein a deflection of the flange portion (6) when the axial load is input to the flange portion (6) formed with the rigid portion (6 a) is increased. Type load sensor. An electric brake device comprising the magnetic load sensor according to claim 1.